Datetime: 2025-03-27 05:19:55 Visit: 4762
Sunflower seed oil production
Sunflower seed raw materials need to be strictly screened to remove impurities (such as stems, leaves, sand and gravel, metal fragments, etc.). Vibrating screens, magnetic separators and other equipment are usually used to ensure the purity of the seeds. The moisture content of the cleaned sunflower seeds needs to be controlled at 8%-10% to facilitate subsequent shelling.
The sunflower seed shell contains more fiber, which will affect the oil yield and needs to be removed by a centrifugal sheller or an impact sheller (the shelling rate is usually 80%-90%). The shelled seed kernels are crushed into 4-6 petals by a crusher to increase the surface area for subsequent steaming and frying.
The crushed seed kernels enter the steaming and frying pan and are heated at 100-110℃ for 15-30 minutes. This process can destroy the cell structure, reduce the viscosity of oil, and denature the protein, thereby increasing the oil yield. After steaming and frying, the material temperature rises to 60-70℃ and the moisture content drops to 5%-7%.
Pressing method: Use a screw press for physical pressing, which is divided into pre-pressing (residual oil about 15%) and full pressing (residual oil 5%-7%). The pressed crude oil needs to be filtered to remove the cake residue.
Leaching method: Use n-hexane and other solvents to extract the pre-pressed cake, and recover the solvent through evaporation and stripping, and the residual oil can be reduced to less than 1%. The leaching method has a higher oil yield, but the solvent residue needs to be strictly controlled.
Crude oil contains impurities such as phospholipids and free fatty acids, which need to be purified by the following steps:
Degumming: Add water or phosphoric acid to hydrate the phospholipids and then centrifuge.
Deacidification: Add alkali (NaOH) to neutralize free fatty acids, generate soap stock and then remove it.
Decolorization: Use activated white clay to adsorb pigments (such as chlorophyll, carotenoids).
Deodorization: Distill to remove odor substances under high temperature (200-250℃) and vacuum conditions.
The refined oil is cooled and filtered, and then tested for acid value, peroxide value and other indicators. If qualified, it is filled with nitrogen for preservation and packaged as finished products. Some products will add antioxidants such as vitamin E to extend the shelf life.
